This invention relates to a method of and apparatus for separating suspended matter from a fluid by centrifugal force, in which the fluid to be treated is directed into a main flow duct of curved configuration where the fluid stream, while moving along a concave surface and past a flow-off edge, produces a stationary whirl maintaining contact with, or partially merging with, the main flow and in which whirl, at appropriate locations, either purified fluid or suspended matter is separated and withdrawn from the whirl while the non-separated portion of the flow volume returns into the main flow stream.
The invention is directed to the problem of providing an optimal arrangement for this method and, to solve this problem, the invention provideds, in each case, to adapt the geometry of the whirl and of the whirl axis to the respective requrements. Thus, in accordance with the invention and starting from a simple cylindrical configuration, the whirl may take any form with a curvilinear axis, even an annular form with a circular axis. Further in accordance with the invention, the whirl, in its radial direction, may be limited by a surface of any suitable form such as, for example, a cylindrical surface, a barrel-shape surface, or any other appropriate curved surface.
In accordance with a development of the invention, the fluid to be treated is directed into a widening and/or narrowing funnel-shaped main flow duct having an annular curved portion along which the fluid flow takes the form of a laminar stream layer and, at the entrance of which, the fluid flow is partly deviated to produce an annular whirl of toroidal configuration either maintaining contact with or partially merging with the laminar portion of the main stream. This development of the invention has the advantage of permitting a space-saving arrangement in tubular pipe systems.
An advantageous embodiment of the invention provides a plurality of whirls arranged either in series, in parallel, or in series and parallel with each other.
In accordance with a further development of the invention, the separation takes place in the whirl chamber, in the zone of the greatest concentration of the specifically heavy phase, and the separated portion is evacuated either into the main stream or into another conduit. This has the advantage that the throughput of the fluid to be treated, per whirl chamber and per unit of time, can be increased.
A further characteristic of the method of the invention is that the separated volume, containing the specifically heavy phase, can be returned into the main stream either at the entrance end or the exit end of the whirl chamber. Thereby, in the same manner as by injection, a driving impulse is imparted to the main stream. A driving effect is also obtained as a result of the separation, because the portion of the volume with the specifically heavy phase preferably is evacuated by suction.
In accordance with the invention, it is sometimes advantageous to direct the fluid to be treated into whirl chambers which are adjacent each other. The volumetric proportion of the fluid to be treated in a single whirl chamber thereby may be increased.
Also in accordance with the invention, compressed air may be added to the fluid to be treated in the zone of the whirl, whereby a further driving effect is produced.
With respect to the separation of the specifically heavy phase from the treated fluid, it is useful to evacuate the particles accumulating at the periphery of the whirl immediately. Within the scope of the invention, such a measure is to be considered as a direct separation close to the whirl.
As a further feature of the invention, the main flow may be directed continuously past one or more whirl zones with the advantage that the process of the invention results in power saving and increased efficiency.
An object of the invention is to provide an improved method of separating suspended matter from a fluid by centrifugal force.
Another object of the invention is to provide improved apparatus for separating suspended matter from a fluid by centrifugal force.
A further object of the invention is to provide such a method and apparatus in which there is produced a stationary whirl of the fluid to be treated which at least maintains contact with a main flow of the fluid to be treated, and in which the geometry of the whirl and of the whirl axis is adapted to the particular requirements of each installation.
For an understanding of the principles of the invention, reference is made to the following description of typical embodiments thereof as illustrated in the accompanying drawings.